1 /* Copyright (c) 2017 Facebook
2 *
3 * This program is free software; you can redistribute it and/or
4 * modify it under the terms of version 2 of the GNU General Public
5 * License as published by the Free Software Foundation.
6 */
7 #include <linux/slab.h>
8 #include <linux/bpf.h>
9
10 #include "map_in_map.h"
11
bpf_map_meta_alloc(int inner_map_ufd)12 struct bpf_map *bpf_map_meta_alloc(int inner_map_ufd)
13 {
14 struct bpf_map *inner_map, *inner_map_meta;
15 struct fd f;
16
17 f = fdget(inner_map_ufd);
18 inner_map = __bpf_map_get(f);
19 if (IS_ERR(inner_map))
20 return inner_map;
21
22 /* prog_array->owner_prog_type and owner_jited
23 * is a runtime binding. Doing static check alone
24 * in the verifier is not enough.
25 */
26 if (inner_map->map_type == BPF_MAP_TYPE_PROG_ARRAY ||
27 inner_map->map_type == BPF_MAP_TYPE_CGROUP_STORAGE) {
28 fdput(f);
29 return ERR_PTR(-ENOTSUPP);
30 }
31
32 /* Does not support >1 level map-in-map */
33 if (inner_map->inner_map_meta) {
34 fdput(f);
35 return ERR_PTR(-EINVAL);
36 }
37
38 inner_map_meta = kzalloc(sizeof(*inner_map_meta), GFP_USER);
39 if (!inner_map_meta) {
40 fdput(f);
41 return ERR_PTR(-ENOMEM);
42 }
43
44 inner_map_meta->map_type = inner_map->map_type;
45 inner_map_meta->key_size = inner_map->key_size;
46 inner_map_meta->value_size = inner_map->value_size;
47 inner_map_meta->map_flags = inner_map->map_flags;
48 inner_map_meta->ops = inner_map->ops;
49 inner_map_meta->max_entries = inner_map->max_entries;
50
51 fdput(f);
52 return inner_map_meta;
53 }
54
bpf_map_meta_free(struct bpf_map * map_meta)55 void bpf_map_meta_free(struct bpf_map *map_meta)
56 {
57 kfree(map_meta);
58 }
59
bpf_map_meta_equal(const struct bpf_map * meta0,const struct bpf_map * meta1)60 bool bpf_map_meta_equal(const struct bpf_map *meta0,
61 const struct bpf_map *meta1)
62 {
63 /* No need to compare ops because it is covered by map_type */
64 return meta0->map_type == meta1->map_type &&
65 meta0->key_size == meta1->key_size &&
66 meta0->value_size == meta1->value_size &&
67 meta0->map_flags == meta1->map_flags &&
68 meta0->max_entries == meta1->max_entries;
69 }
70
bpf_map_fd_get_ptr(struct bpf_map * map,struct file * map_file,int ufd)71 void *bpf_map_fd_get_ptr(struct bpf_map *map,
72 struct file *map_file /* not used */,
73 int ufd)
74 {
75 struct bpf_map *inner_map;
76 struct fd f;
77
78 f = fdget(ufd);
79 inner_map = __bpf_map_get(f);
80 if (IS_ERR(inner_map))
81 return inner_map;
82
83 if (bpf_map_meta_equal(map->inner_map_meta, inner_map))
84 inner_map = bpf_map_inc(inner_map, false);
85 else
86 inner_map = ERR_PTR(-EINVAL);
87
88 fdput(f);
89 return inner_map;
90 }
91
bpf_map_fd_put_ptr(void * ptr)92 void bpf_map_fd_put_ptr(void *ptr)
93 {
94 /* ptr->ops->map_free() has to go through one
95 * rcu grace period by itself.
96 */
97 bpf_map_put(ptr);
98 }
99
bpf_map_fd_sys_lookup_elem(void * ptr)100 u32 bpf_map_fd_sys_lookup_elem(void *ptr)
101 {
102 return ((struct bpf_map *)ptr)->id;
103 }
104
